For an ultrasonic image processing device employed in medical diagnostic imaging, there is disclosed a method in which, as described in, for example, patent literature 1, a modulus-of-elasticity distribution in a tissue is estimated based on a magnitude of a change in a small area in a diagnostic motion picture, and hardness is converted into a color map and then displayed. However, when the tissue border is noted in order to perform modulus-of-elasticity processing, sharpness is found to be degraded. As described in patent literature 2, a technique of producing a scalar distribution image directly from motion vectors of a diagnostic motion picture so as to improve the degree of distinction of the tissue border is available.
In order to remove a noise from a vector distribution, a low-pass filter for uniform smoothing is, as described in, for example, patent literature 3, adopted. In a B-mode image (a scalar distribution of brightness), a similarity filter that retains the sharpness of an edge while removing the noise has been invented in the patent literature 3.